Function ufunc_at

numpy/core/src/umath/ufunc_object.c:6248–6526

* Call ufunc only on selected array items and store result in first operand. * For add ufunc, method call is equivalent to op1[idx] += op2 with no * buffering of the first operand. * Arguments: * op1 - First operand to ufunc * idx - Indices that are applied to first operand. Equivalent to op1[idx]. * op2 - Second operand to ufunc (if needed). Must be able to broadcast * over first ope

 *       over first operand.
 */
static PyObject *
ufunc_at(PyUFuncObject *ufunc, PyObject *args)
{
    PyObject *op1 = NULL;
    PyObject *idx = NULL;
    PyObject *op2 = NULL;
    PyArrayObject *op1_array = NULL;
    PyArrayObject *op2_array = NULL;
    PyArrayMapIterObject *iter = NULL;
    PyArrayIterObject *iter2 = NULL;
    PyArray_Descr *operation_descrs[3] = {NULL, NULL, NULL};

    int nop;

    /* override vars */
    int errval;
    PyObject *override = NULL;
    int res = -1;   /* start with fail condition so "goto fail" will error */

    PyArrayMethod_StridedLoop *strided_loop;
    NpyAuxData *auxdata = NULL;

    if (ufunc->core_enabled) {
        PyErr_Format(PyExc_TypeError,
            "%s.at does not support ufunc with non-trivial signature: %s has signature %s.",
            ufunc->name, ufunc->name, ufunc->core_signature);
        return NULL;
    }

    if (ufunc->nin > 2) {
        PyErr_SetString(PyExc_ValueError,
            "Only unary and binary ufuncs supported at this time");
        return NULL;
    }

    if (ufunc->nout != 1) {
        PyErr_SetString(PyExc_ValueError,
            "Only single output ufuncs supported at this time");
        return NULL;
    }

    if (!PyArg_ParseTuple(args, "OO|O:at", &op1, &idx, &op2)) {
        return NULL;
    }

    if (ufunc->nin == 2 && op2 == NULL) {
        PyErr_SetString(PyExc_ValueError,
                        "second operand needed for ufunc");
        return NULL;
    }

    if (ufunc->nin == 1 && op2 != NULL) {
        PyErr_SetString(PyExc_ValueError,
                        "second operand provided when ufunc is unary");
        return NULL;
    }
    errval = PyUFunc_CheckOverride(ufunc, "at",
            args, NULL, NULL, NULL, 0, NULL, &override);